Old folks hunting for flings exploded last year as seniors gleefully look to play the field online.

Ourtime.com membership sprung from 1 million to 2.5 million singles in just the last nine months, and now the three biggest love sites for grannys and granpops — Senior People Meet, Seniors Meet and Ourtime.com — share more than four million people combined.

“I have hundreds of men trying to hang out with me,” 68-year-old Liz Defore brags of her online dating frenzy.

The Southern California native joined a slew of dating sites last year after breaking up with her 48-year-old boy toy. Now she basks in male attention as more than 600 men have come running after her self-described girlish looks and youthful mind. Meanwhile, she happily scours profiles, finding herself hot metrosexuals who slather on moisturizer, manicure their fingernails and ball out at rock concerts.

Grey-haired singles like Defore are happily recharging their love lives online as each one averages 10 messages a month from potential partners and gets their profiles checked out 50 times every 30 days.

And the fun leaps right from the computer into the bedroom. Seniors are catching STDs at record rates; the number of 50, 60 and 70 year olds getting chlamydia, syphilis and gonorrhea doubled in the past decade. The US Center for Disease Control and Prevention reports cases of chlamydia and syphilis in older kin ballooning to more than 19,000 and 2,500, respectively.

Longer life expectancy, climbing divorce rates and recharged libidos are behind the surge in online and offline love affairs.

“I went out on a date at least once a week. You know there are things that are fun in life, and that was fun for me!” gushes 68-year-old Judy Tatman of her escapades following her husband’s death.

She rendezvoused with more than 35 suitors over her year of using Ourtime.com and gallivanted around the country from Oregon and Arizona to Kansas and New York. Tatman indulged in tasty home-cooked meals, lovely homes and at least one Jacuzzi sex-fest with an online catch.

“I thought, oh my God, I hardly know this man! This is ridiculous!” she giggled.

Shirtless, weathered men snapped and emailed photos of themselves for Tatman’s delight, and others even sexily undressed in front of their Web cams. One man sent her a picture of his manhood for her viewing pleasure.

“And I’m thinking, is this supposed to make me hot or something?” she laughed.

Her online studs varied in shape, size, color and age. Some men as young as their thirties happily went after her. “They were younger than my son! But I’m a pretty chick,” she said.

Tatman and Defore claim they’re conservative when it comes to jumping into the sack though. The former slept with three men, including her current live-in partner, during her year-long online dating venture. Meanwhile, Defore hasn’t met anyone sexy enough to jump into the sack with yet.

“Ew, yuck! They look too old. Or they don’t have teeth. They’re yahoos with baseball caps!” she says.